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A mentally ill man in Florida who died after a gunfight with cops had just gunned down his mother’s friend for making a move on his imaginary girlfriend, authorities said.

Brian DiSario, a 30-year-old man with a history of mental illness, fatally shot David Armstrong, 56, after accusing him of making a romantic pass at his nonexistent lover as they were inside a garage in Port Richey on Thursday, the Tampa Bay Times reports. The suspect’s mother and her boyfriend were also in the room at the time of the shooting.

“Please note: Brian does not have a girlfriend,” Pasco Sheriff Chris Nocco told reporters during a press conference Thursday. “In his mind, he did, but in reality, he didn’t.”

Nocco said DiSario accused Armstrong of “messing with” his girlfriend before pulling out a gun and shooting him. DiSario then went into the home to get another gun and shot Armstrong again, killing him, Nocco said.

DiSario’s mother and her boyfriend fled to a neighbor’s house and DiSario headed to Gulf Island Drive, where cops found him standing in the middle of the street.

An “absolute gun battle in the middle of the street” erupted between cops and the suspect before he managed to run back home — where he was known to have a gun collection and a stockpile of ammunition.

A sheriff’s office robot later found DiSario’s body, WTSP reports. It was not clear if he killed himself or died of shots fired by police, none of whom were injured during the gunfight.

Armstrong’s body was found inside the garage.

Deputies are now working with federal authorities to find out whether DiSario was a legal gun owner, the Tampa Bay Times reports.